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Battery Move

Scottc

Junior Member
I originally posted this in another section but thought this one is more appropriate.

I have a 1970 35 MKII. Currently the batteries were moved to the center of the boat over the keel where the dinette would be. I want to get that space back. I installed a porta potti with a 5 gallon holding tank enclosed. I then removed the holding tank under the dinette seating on port side at the bulk head. I plan on putting my batteries there. I can fit 3 house batteries form the size I currently have. Now there are 4 and they are wired with two in series and the whole thing in parrallel. I want to just have the 3 in parrallel. I don't understand why they would have been wired the previous way. Any ideas? Also any ideas on what I am doing as good or bad. I love my boat and am trying to get it back to being pretty again. It has been a serious ocean racer with the previous owner and he did a great job setting the boat up mechanically.

Scott
 

steven

Sustaining Member
I have two house batteries under the port settee. The extra weight there helps a little to offset the seemingly typical E35-2 starb. list. Only drawback is long run to the distribution panel - about 12 feet. I used #8 wire (expensive). Mine are boxed to make the insurance guys are happy, and anchored so they won't move around when sailing. Also - it's a bit hard to get to them for maintenance. Under the quarter bearth might have been a better place - but I don't think there is quite enough room for two.

If your battery wiring is in series, it was probably intended for two pair of 6v golf car batteries.

--Steve
 

Dave N

Member III
I have 3 27s(house) and 1 24(starter) under the quarter berth. I will try and post a pic.
 

exoduse35

Sustaining Member
My batteries are in the same place you are intending. I was able to squeeze in 4 group 31 AGMs in that little hole by placing them with the long battery side against the bulkhead and 2 rows side by side. I needed to cut a keyway into the bench top as the last one will not go in through the hatch but cutting the hatch wider for the last one and making a new lid was easy and solved the problem. If I were to do it again, I would put a group 27 in the forward port corner and use it as a starting battery. My solution was to put a small battery under the foot well on the starboard side. I think it was a group 58. I have the A4, but want the diesel and there is not enough battery to kick it over for long so if I make the conversion I will need another plan.
Edd, E35-2 #164
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
My batteries are in the same place you are intending. I was able to squeeze in 4 group 31 AGMs in that little hole by placing them with the long battery side against the bulkhead and 2 rows side by side. I needed to cut a keyway into the bench top as the last one will not go in through the hatch but cutting the hatch wider for the last one and making a new lid was easy and solved the problem. If I were to do it again, I would put a group 27 in the forward port corner and use it as a starting battery. My solution was to put a small battery under the foot well on the starboard side. I think it was a group 58. I have the A4, but want the diesel and there is not enough battery to kick it over for long so if I make the conversion I will need another plan. Edd, E35-2 #164
i

You might want to double check the amount of cranking amps you would need for a starting battery. I recall talking to a diesel mechanic about this and his comment that most folks do not realize how relatively small a battery can be to reliably start a three cylinder diesel like mine.

I cannot know your location's limitations, but do know that a group 24 is more than sufficient for our engine, and it's not too physically large.
I have an AGM group 27 for my emergency/starting battery, and it starts our engine several times a season as a test, and performs just like the main house bank of two large CG batteries.
(I should note that the house bank is flooded technology, and the only reason for the AGM starting battery is that it had to be installed in a near-inaccessable area under the aft berth.)

My experiences, for what they're worth.
Loren
 
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mherrcat

Contributing Partner
So how many "cranking amps" are necessary to start a two or three cylinder diesel engine? I have been thinking for a while about adding a dedicated starting battery but have very little room for an additional full-size lead/acid or AGM type battery, but there are several very small Lithium Ion batteries out there, mostly for motorcycle or racing applications, that might do the job.
 

toddster

Curator of Broken Parts
Blogs Author
Well... it depends. We start our old 3 cylinder tractors with fairly small automotive batteries. But if they haven't run for a while, and it's cold, it usually takes a booster. Nice to have some excess capacity on hand, unless you're always going to have the sag wagon five minutes away.

At the other end of the scale... I got caught away from home a couple of weeks ago, after midnight on a sunday morning, with a dead alternator on Suburbasaurus. Had to call a tow truck for a jump. The only guy who would come out had no idea how to boost a big diesel - showed up with two of those little booster gadgets from Harbor Freight. He might as well have brought AA batteries. But that's a completely different story which I'll spare you.
 
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Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Same question as Mark. I have two 27s, either of which starts the M25 without a strain. Only one battery is used, leaving the other in reserve.

So, with newish house batteries, what is the need for a dedicated starter? Wouldn't running the engine daily keep up with the minimal drains of even a week-long cruise?
 

Frank Langer

1984 Ericson 30+, Nanaimo, BC
Hi Mark,

I can't answer your question about what size battery is needed, but I have a suggestion for where to put an additional battery (given that you and I have essentially the same boat, ours being 1984 E30+). I have two deep cycle group 27 house batteries in the battery compartment below the quarterberth, and a group 24 starting battery in the port cockpit locker. This starting battery is placed on a small shelf on the right forward side of the cockpit locker when looking into the locker. It is actually placed right behind the galley sink on the other side of that bulkhead. It is well-positioned for battery connection to the engine, alternator, etc.

Although I would like to have more battery power, the current configuration works well for us. I would like to replace the house battery with group 31 size 6 volt golf cart batteries, but so far the ones I've found are too tall to fit in the locker underneath the quarterberth.

Hope that helps.

Frank
 

toddster

Curator of Broken Parts
Blogs Author
Same question as Mark. I have two 27s, either of which starts the M25 without a strain. Only one battery is used, leaving the other in reserve.

So, with newish house batteries, what is the need for a dedicated starter? Wouldn't running the engine daily keep up with the minimal drains of even a week-long cruise?

Off the top of my head, I can't give as good an answer as the usual maintenance reference books, but starting batteries are fundamentally different from house batteries. It has to do with the number and thickness of the lead plates inside. Starting batteries are designed for quick high-amperage discharge, quick charge, and can be damaged by deep cycling. (Also why they are useful for windlass & similar loads.) House batteries can be damaged by those quick high-amp loads.

However, for the relatively small motors used on small- and medium-sized sailboats, it may not be as critical an issue as it is for big motor yachts.
 

Rocinante33

Contributing Partner
I wonder what the starting battery is on a Kubota Bobcat? It may be a good reference point for those of us with Kubota based engines.
 

sailorman37

Member II
Mark,

As Frank described, my batteries are in a similar place. I have two 6 volt golf cart batteries under the qrt berth and then a group 24 starting battery sitting on the plywood above the fuel tank. As Frank mentioned, the 6 volt batteries are taller so I had to redo the quarter berth shelf to allow them to fit. I use an on/off switch for the house bank and a 1/both/2 switch for the starting battery. If for some reason I ever needed the house battery to start the engine I could switch over. The 1/both/2 switch is stuffed down by the starting battery to hopefully prevent someone from switching it inadvertently and draining the starting battery. The alternator then feeds the common leg of that switch so I can direct where the total charge goes instead of a battery isolator device.
 

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mherrcat

Contributing Partner
Here is a link to the type of battery I was referring to:

http://antigravitybatteries.com/small-case-batteries/

Some of them have over 400 cranking amps, but I wonder if they could be integrated into the types of charging systems used on most boats. The literature says specifically not to use chargers typically used for lead/acid batteries. They also specifically say they are not intended for passenger car use.

But they are tiny!
 

sailorman37

Member II
Here is a link to the type of battery I was referring to:

http://antigravitybatteries.com/small-case-batteries/

Some of them have over 400 cranking amps, but I wonder if they could be integrated into the types of charging systems used on most boats. The literature says specifically not to use chargers typically used for lead/acid batteries. They also specifically say they are not intended for passenger car use.

But they are tiny!

They are cute little batteries, but at a price! Since they are so small, you may consider taking it out to recharge and it does say it can hold the charge for one year. Although the 1601 seems to have enough cranking amps, it's reserve capacity is a bit lower than the lead acid battery. I believe the conversion of RC to Ah formula is RC divided by 2 plus 16. So my lead acid battery would be 70/2 + 16 or 51 Ah compared to the 16 Ah mentioned for their 1601 battery. However, if you try to go backwards with the formula you get 0 minutes reserve capacity. I guess you only get one shot at starting the battery:)
 
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